To generate a 2.5D view, you need a script that defines the material stack using a specialized version of the KLayout DRC language Navigate to New 2.5d Script This opens the Macro Editor with a template script. Define your layer stack using the functions. 3. Scripting Basics The script tells
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input(layer_index, datatype) : Fetches shapes from the 2D layout.
The 2.5D view is a specialized tool that transforms flat, 2D layout layers into extruded 3D blocks. Each layer in your GDS file is assigned a thickness and stacked vertically to create a 3D representation. This makes it ideal for visualizing vertical layer relationships, understanding complex process stacks, and identifying metal wiring congestion in dense designs.
The name is a precise technical definition: the 2.5D view creates a of your chip layout. It's not a full, continuous 3D model of the process topology. Instead, it takes your existing 2D layout layers and "extrudes" them vertically, assigning each layer a specific thickness and height. Imagine a 2D blueprint of a multi-story building; the 2.5D view lifts each floor up to its corresponding height, turning a flat plan into a stack of extruded shapes. klayout 25d view
The baseline elevation where the layer begins relative to the substrate (
Unlike a true 3D CAD program, KLayout uses "pseudo-3D" or . This means it takes the 2D shapes on your layers and extrudes them vertically according to a Layer Properties file or a Technique definition. It is particularly useful for checking overlaps, vias, and structural heights in MEMS, photonics, or IC design. Key Features
Large GDSII or OASIS files can bog down your computer if you try to render the entire chip in 25D. Use these best practices to ensure peak performance: 1. Limit the Region of Interest (ROI)
The 2.5D window uses a camera-based navigation system relative to a pivot point marked by a compass icon. Drag with Right Mouse Button Move Pivot (Up/Down/Left/Right) Drag with Middle Mouse Button Move Pivot (Forward/Backward) Mouse Wheel Zoom (Magnify/Shrink) Ctrl + Mouse Wheel Top-Down View Toggle Press and Hold Shift Scaling the Z-Axis To generate a 2
For decades, integrated circuit (IC) layout engineers have relied on two-dimensional, top-down views to design chips. But as process nodes shrink and designs grow in complexity, a purely planar perspective often obscures critical relationships between layers. This is where comes into play.
The vertical height to which the 2D polygon will be extruded.
z(input_object, zstart:..., zstop:..., name: "layer_name") : Extrudes the input object from zstart to zstop . Example:
What are you using? (e.g., CMOS, MEMS, Photonics) Scripting Basics The script tells This public link
Consider a real-world scenario. A design engineer runs LVS (Layout vs. Schematic) and receives a mismatch in an analog block. The error points to an NMOS transistor that should have an N-well implant but does not. The 2D view shows overlapping polygons, but the hierarchy is deep.
Provides hardware-accelerated, smooth rotation and zooming. Best for large layouts.
This approach is incredibly effective at revealing the between different physical layers of the design, such as metal wires, polysilicon gates, and active areas. This visualization makes it much easier to spot issues like wiring congestion in a 3D space or to understand the physical stack-up of your process.